A spare-tire is an additional tire carried in a vehicle intended as a replacement for a road-wheel that is no longer functioning. The term “spare-tire” is actually a misnomer, as the spare-tire is actually an assembly that has a tire mounted on a wheel ready for immediate use, although other systems have been used. A spare-tire could also be a spare wheel that has no tire in the assembly at all. A road-wheel is a vehicle wheel which may contact the ground and support the vehicle as the vehicle moves over the ground.
A spare-tire may be carried in the vehicle in various locations. Spare-tires have been stored in a spare-tire well, which is a recessed area in the trunk of a vehicle, usually in the center. A stiff sheet of cardboard may lie on top of the spare-tire well with the trunk carpet on top of it to hide the spare-tire and provide a pleasant look to and a flat surface for the trunk space. In mid-engined and rear-engined cars, the spare-tire may be stored in the front boot, which is similar to storage in the trunk. Some vehicles have even stored the spare-tire in the engine bay. Vehicles have also stored the spare-tire in the interior compartment of the vehicle or in a cargo area of the vehicle.
Vehicles have also mounted the spare-tire externally, such as on the rear gate, roof, side, or on the hood or bonnet of the vehicle. Other external storage solutions include storing the spare-tire underneath the vehicle. The under-vehicle hung spare-tire has advantages over storing the tire inside the vehicle, including saving interior space and not having to access panels, move seats, or empty/move cargo to access the wheel. However, it may be desired to manage the movement of the under-vehicle hung spare-tire during a collision.